What are the answer choices, if there are any?
Answer:
The answer is a wedge.
Explanation:
The wedge is a combination of two inclined planes. It is used to separate bodies which are held together by large forces, e.g, splitting timber
M.A.= slant height of wedge/thickness of wedge.
Hence a long thin wedge has a higher mechanical advantage than a short thick one; or the smaller the angle theta between the slant heights, the greater the mechanical advantage.
Here since both children and merry go round is our system and there is no torque acting on this system
So we will use angular momentum conservation in this

now here we have



Now when children come to the position of half radius
then we will have



now from above equation we have

